As shown in FIGS. 7 and 8, a prior art rack is formed of a plurality of upright support rods 3 and shelves 8 which are fastened with the support rods 3 by a plurality of fastening sleeves 81 in conjunction with a plurality of locating sleeves 7. The fastening sleeves 81 are of a tapered construction and are fastened fixedly at corners of the shelves 8. The locating sleeves 7 are of a tapered construction and composed of two pieces which are provided in the inner wall thereof with a retaining protrusion 71. The upright support rods 3 are provided in the outer surface thereof with a plurality of retaining slots 31, which are arranged at an interval. In combination, the locating sleeves 7 are first fastened at the desired levels of the upright support rods 3 such that the retaining protrusions 71 of the locating sleeves 7 are securely retained in the retaining slots 31 of the support rods 3. The shelves 8 are then located at the desired levels of the support rods 3 by fitting the fastening sleeves 81 over the locating sleeves 7 such that the fastening sleeves 81 of the shelves 8 are located by the locating sleeves 7.
The prior art rack described above is defective in design in that it is rather time-consuming to add or reduce shelves 8 of the rack because of the fact that the existing shelves 8 must be first dismantled. In addition, when two or more racks of the prior art are joined together, the shelves 8 of one rack can not be flush with the shelves 8 of other rack, as shown in FIG. 8.